The German Offenlegungsschrift 34 22 658 discloses straw briqueting equipment with a screw compactor of which the driven, rotating screw evinces an outer contour at its front end, as seen in the direction of advance, determined by two screw coils away from a conical screw core. The conical segment of the otherwise cylindrical screw enters a conical compaction space of a screw housing entered by the cantilevered worm. A hopper feeding the straw to be briqueted is mounted above the cylindrical part of the screw and said straw is compacted by said rotating screw in the conical screw segment and is expelled through a discharge opening at the tapered end of the conical surface of the screw housing. The pressure of the conical screw compactor can be controlled by a tubular, cross-sectionally adjustable punch adjoining the discharge of the conical surface.
The straw to be briqueted is highly compressed by the pressure from the conical screw compactor and heats up in this process and on account of its lignin content cakes into a straw cake which even when hot flows only poorly. Because accumulation may take place especially at the transition from the inner cone of the screw housing to the cavity, whereby the discharge aperture of the conical worm compactor would clog, an axially displaceable plunger is mounted in the screw of the German Offenlegungsschrift 34 22 658 to periodically expel the accumulating compacted straw into the cavity. However it has been found that the straw lignin not only makes possible briqueting, but also bonds the plunger guided displaceably in the screw to this screw until it can no longer move. The known equipment therefore can be operated only during comparatively short intervals before requiring disassembly and cleaning.
The object of the invention is to create equipment of the species in such manner that continuous operation unlikely to incur malfunctions shall be achieved.
This problem is solved by the features of present invention.